This invention relates to an improvement for diving suits. In particular, this invention relates to a thermal liner for diving suits that provides thermal protection using stored energy from phase change materials.
The rigors associated with diving are many. Surviving and capably functioning in the cold temperatures are problems as old as diving itself. Water conducts heat away from the human body 25 times faster in water than in air, and the heat capacity of water is greater than that of air by more than 3500 times. The significant difference between rates of heat loss at similar temperatures in air and when immersed in cold water creates a distinct difference in the physiological effects associated with the two. Immersion in extreme cold water incurs serious physiological effects that are potentially dangerous for a diver.
Consequently, several protective diving suits have evolved that make underwater tasks less difficult. Specifically, several forms of thermal protection systems exist to allow divers to operate safely when diving in severe cold environments. These include active heating systems that contain electrical resistive elements in the suit, or systems that provide a flow of warm water to a heat distribution garment worn by the diver. Unfortunately, both active heating systems offer negligible protection to the diver in the event of power failure to the electrically-heated suit, or interruption of water flow to the hot-water suit. Severe thermal stress to the diver can result without the presence of some type of emergency backup.
With the hot-water suit, warm water at approximately 100.degree. F. is pumped into a loose outer garment to surround the diver with a layer of hot water for thermal protection. The hot water supply provides excellent thermal protection to divers in cold water as long as the water supply continues; however, the suit offers no real protection for a diver in an emergency when the supply of hot water is interrupted. Water temperatures in the suit have been shown to drop to dangerously low levels in just a few minutes after the cutoff of the hot water supply.
Wearing an electrically heated suit is not without its dangers. Interruption of power to the electrical suit can and does subject a diver to hazardous temperature conditions soon.
Besides the emergency situations described above, instances of cold water exposure sometimes occur during normal diving operations, even when the hot water flow is uninterrupted. Currently, divers wear conventional dive liners inside their hot-water suits; these dive liners prevent scalding of the divers if the temperature of the water entering the suits is too high. However, these liners do not offer any significant protection against cold in the event of water flow interruption. Additionally, in the midst of a mission, there are several causes of exposure to cold with the conventional liner even while the flow of hot water continues. The first of these occurs when the diver bends over or bends at the joints. In this situation, the joint presses against the outer garment of the loose fitting suit as the hot water is momentarily squeezed out of that particular area. This creates a "thermal short" which exposes an area of the diver to cold water exposure. Another instance in which cold water exposure routinely occurs is the performance of a mission in which the diver is standing in a water current. The current may push the suit against the diver's body, thus creating the same thermal short effect across even larger areas of a diver's body. The use of equipment that presses against the hot-water suit is another common way that body heat can pass from a diver.
Thus, in accordance with this inventive concept, a need has been recognized in the state of the art for overcoming the deficiencies of existing diving suits by providing a thin suit liner that contains stored energy in the form of latent heat that protects the diver against heat loss upon failure of the heat supply of the diving suit and is incompressible to prevent thermal shorts between the diver's skin and the diving suit.